The cleansing of skin with surface-active cleasning preparations has become a focus of great interest. Many people wash and scrub their skin with various surface-active preparations several times a day. Ideal skin cleansers should cleanse the skin gently, causing little or no irritation, without defatting and overdrying the skin or leaving it taut after frequent routine use. Most lathering soaps, liquids or bars fail in this respect.
As background, reduced skin irritation benefits as measured by patch testing of cationic and nonionic types of polymers are set out in "Polymer JR for Skin Care" Bulletin, by Union Carbide, 1977. The cationic polymers are reported to be preferred over the other polymers because they provide better skin feel benefits.
Attention is directed to J.K.P. No. Sho 58 [1983] 167700, Ohata, et al., which teaches a soap bar with 0.1-6% cationic poly(diethyldiallylammonium chloride) and copolymers thereof. Ohata et al. appears to recognize a problem with the use of other cationic polymers and teach away from the use of the other polymers including JR400.
Attention is directed to U.S. Pat. No. 3,761,418, to Parran, Jr., issued 9/25/73, which discloses detergent compositions containing particle deposition enhancing agents comprising a water-insoluble particulate-cationic polymer mixture. Hydrated cationic guar gum polymers are not mentioned. Parran, Jr.'s Example XV is a 50:50 tallow/coconut (T/CN) fatty acid soap bar which contains 3% cationic polymer. The preparation of the bar, however, is not specified. U.S. Pat. No. 4,012,341, to Orshitzer/Macander, issued 3/15/77, discloses an all-synthetic detergent shampoo bar comprising a mixture of anionic and nonionic detergents. The bars of Examples 2 and 4 contain 1% JR 400. Cationic guar gum polymers are not taught.
U.S. Pat. No. 4,338,211, Stiros, issued July 6, 1982, discloses a liquid skin cleanser with 2.3% to 3% of a synthetic surfactant, polymer JR-400, small amounts of free fatty acid, plus a fatty acid alkylolamide as lather boosting agents.
EPA 106,193, Turney, published 4/25/84, assigned to Union Carbide Corp., teaches liquid skin cleansers with anionic detergent, fatty acid soap and cationic polymer. Soap bars are not taught in either Stiros or Turney.
UK Pat. Appln. GB2094307A, published 9/15/82, assigned to Johnson and Johnson Baby Products Co., discloses amphoteric-fatty acid complexes for detergent products which exhibit good foam and low occular irritancy. This reference teaches that anionic surfactants should not exceed 20% to assure low occular irritancy. Cationic Polymer JR at levels of 0.5 to 3.0% is taught. Liquids and bars are disclosed. Cationic guar gum polymers are not disclosed and skin mildness is not discussed.
Attention is also directed to U.S. Pat. No. 4,234,464, to Morshauser, which issued 11/18/80. This reference discloses a detergent synbar in Example 6 which comprises: 45% isethionate, 5% alkyl amide, 37.5% stearic (C.sub.18) acid, 5.0% hydrogenated tallow glycerides and 1% Polymer JR. This patent also discloses a wide range of synthetic surfactants and fatty materials. The synbars comprise up to 5% soap "without substantial detriment" and up to 1.5% cationic polymer. Cationic guar gums are not mentioned.
U.S. Pat. No. 4,491,539, James J. Hoskins and Adriaan Kessler, issued Jan. 1, 1985, discloses liquid cleansing products comprising about 5% to 30% of surfactant, about 0.1% to about 1.0% of guar material, about 0.15% to about 1.0% of nonionic carboxyvinyl polymer, and water. Soap bar compositions are not disclosed. Another reference is British Pat. No. 2,103,236A, Colgate, Feb. 16, 1984, which discloses a liquid detergent containing guar gum and a ternary surfactant mixture including a betaine. Soap bar compositions are not disclosed. Also, British Pat. No. 2,114,994A, L'Oreal, Sept. 1, 1983, discloses a cleansing product based on acylisethionates and cationic polymers. These products are not based on soap.
Although it is known that cationic polymers provide hair and skin conditioning properties, none of the above references teach the use of low levels of hydrated cationic guar gum polymers in a soap-based bar. None indicate that the important in-use soap bar characteristics (lather character and volume, rinsing, soap bar feel, etc.) are preserved in the presence of polymers. None indicate that the hydrated cationic guar gum polymers must be well hydrated, incorporated and dispersed in the soap bar in order to achieve improved mildness while maintaining desirable soap bar properties.
It was indeed surprising and unexpected that low levels of hydrated cationic guar gum polymers would provide mildness in a soap-based bar that is nearly equal to synbar products based on mild synthetic surfactants, while maintaining desirable bar soap properties. It was unexpected that the hydration of the cationic guar gum polymers was necessary in order to achieve good incorporation into the soap bar which in turn leads to the mildness and maintenance of soap bar properties.